This application is a continuation of provisional application No. 60/021,721, filed Jul. 15, 1996 by Knox entitled xe2x80x9cWireless stereophonic transmitter and receiver/tuner system.xe2x80x9d The cable television industry developed and refined a process of audio signal compression in the mid-1980""s. The process allows for extra space on coaxial cable wire by electronically compressing audio signals between the video bandwidths that carry the television signal. By the late 1980""s, audio signal compression technology spawned an industry that has come to be known as xe2x80x9cdigital music.xe2x80x9d Digital music is developed by cable conglomerates and is sold to subscribers along with their cable television service. This audio music signal is produced at one location by using multiple compact disc players playing continuous music in a variety of formats then sent via satellite to local cable companies. The audio music service is also currently available as a premium service via direct broadcast satellite (DBS), but other methods, such as fiber optics, telephone systems, microwaves, or Internet enabled technologies for example, could also deliver the signal.
The local multisystem operators (cable and DBS companies sell the service to subscribers who pay a monthly fee for a headunit or xe2x80x9ctunerxe2x80x9d) compress the signal, then sell the service to subscribers. This unit decompresses the audio signal, then converts it into an analog signal which can be heard through the television audio source or be used in conjunction with a home stereo component system. The user can choose from multiple channels using an infrared remote control or with tuner controls located on the headunit. With the Digital Music Express product, including song title, artist, album, and record label can be viewed on an LCD (liquid crystal display) window located on the infrared remote that operates the tuner as described in U.S. Pat. No. 5,445,570. This system to Cook correctly postulates the value of listener access to program information; specifically, that there is a strong possibility for loss of revenue due to subscription cancellation if a subscriber has no method of knowing the program information that corresponds to the song they are listening to. Furthermore, Cook explains that to the music industry, identification of the recording label and the musical selection is critical to the sale of recordings.
Digital music has not developed as proponents predicted. Since its national introduction in the early 1990""s, sales penetration has been an unimpressive 1.5-2.5 percent among the multisystem operators offering the service. Research has revealed that digital audio is a unique product, but with very little recognition among subscribers. And, despite a myriad of marketing schemes, neither operators nor the two major cable audio producers can claim to have found a definitive solution to drive sales.
The problem with the current product is that it is not versatile. It can only interface with an existing stereo component or loudspeaker system. Subscribers are also bound to a single choice of music located in the room where the converter/tuner box is located. Because the cable music service is not available in the convenience of technology such as a portable disc player, a portable bookshelf stereo, a portable radio/tape player, or more popular mediums for listening to electronic music, it will never be as attractive as it could be to the consumers who would most appreciate its advantages.
As mentioned above, presently, the only means to access the audio signal provided by the cable music services is through use of a stationary output device, such as a rack stereo system with auxiliary inputs for the digital music tuner. U.S. Pat. No. 5,282,028 entitled xe2x80x9cRemote Control for Digital Music Terminal with Synchronized Communicationsxe2x80x9d and U.S. Pat. No. 5,455,570 entitled xe2x80x9cMethods And Apparatus For Communication Program Data Signals Via A Remote Control Unitxe2x80x9d incorporated herein by reference, disclose systems wherein an infrared remote controls and communicates with a digital music tuner. To use the tuner, changing channels or viewing program information, the listener must be close enough in proximity to the tuner to use the infrared remote; this can be frustrating if a variety of formats or program information is of interest to a listener who within sound range but out of the reception range of the remote control. Also, only one music channel can be accessed at a time, limiting all listeners to a single music format. Additionally, if currently available tuners were combined with multiple output devices in a single structure, competing tastes in music preference and volume would contribute to unnecessary costs and unwanted noise pollution. Prior art has recognized the value in wireless stereophonic signals. U.S. Pat. No. 4,829,570 to Borchardt describes a F.M. (frequency modulation) signal transmitter/receiver system which is then outputted to loudspeakers. The Borchardt system converts an audio signal into a F.M. signal, transmits the F.M. signal over A.C. power lines, and reconverts the F.M. signal into an audio signal which is outputted at the source. The problem with such a device is that it has limited function. Only one signal is sent from the transmitter to the receiver. The receiver must be a stationary device with auxiliary inputs to accommodate the transmitted signal. And, the listener must return to the signal source to change the input. RF Link markets a similar product, Wavecom Jr., that transmits audio and video signals on a gigahertz frequency, but is subject to the same limitations of the Borchardt system. U.S. Pat. No. 5,491,839 entitled xe2x80x9cSystem For Short Range Transmission Of A Plurality Of Signals Simultaneously Over The Air Using High Frequency Carriersxe2x80x9d to Schotz discloses a system for transmitting analog or digital signals. Schotz suggests that three electrical input signals be comprised of conventional audio sources, such as a compact disk, or tape deck, but not digital audio or program information to a plurality of receiver/tuners that allow a listener to interact with the music service.
In general, such prior art systems are limited in range, signal strength, variety of channels, program information available, and overall accessibility and ease of use. Consequently, a requirement exists for a local transmitter and digital receiver/tuner system that communicates under a control to provide reception of the digital audio music and display of corresponding program information which can be located at the convenience and discretion of multiple listeners.
It is, therefore, the object of the present to provide a wireless local transmitter and digital receiver/tuner system for transmitting and receiving digital audio and corresponding program information that will overcome the limitations of conventional methods of transmitting and receiving digital audio and corresponding program information.
It is another object of this invention to provide a transmitter that can receive digital audio and program information input from a plurality of sources and can simultaneously broadcast a plurality of digital audio and program information signals over a limited range.
It is still another object of this invention to provide a transmitter that can simultaneously broadcast a plurality of digital audio and program information signals via a combined digital signal.
It is an additional object of this invention to provide receivers that can simultaneously receive a plurality of combined digital audio and program information signals broadcast by the transmitter, and can select one of the digital audio signals and display corresponding program information signals broadcast from the transmitter.
It is still an additional object of the present invention to utilize an existing clock oscillator having a predefined frequency within a first and second device to enable the transmission and reception of digital audio and program information between the two devices using the predefined frequency to generate a wireless digital carrier signal.
It is a further object of the present invention to provide a two-way communications link between a plurality of receiver/tuners and the first controllable device which allows the listener to interact with the service with, for example, viewing program information, participate in surveys of music preferences, or storing program information for future use, or purchase of music via electronic accounts.
It is yet a further object of the present invention to provide an error detecting or an error checking process for receiving an entire, error-free message from a predetermined number of transmissions between a controllable device and a receiver/tuner of a message defined by a predetermined number of data fields.